A couple of years ago I purchased a DBS-22. Until yesterday it has been sitting with a partially sharpened 1/2" drill bit in it. Yesterday I completed sharpening it. It wasn't too difficult to do after watching Alan Holtham' s well done video. If I would have stopped there, I would have thought that is easy.
The second 1/2" bit didn't go as well. I had not taken the time to read the DBS-22 operator's manual since I had watched the video a couple of times. That is not a good idea as there is some pertinent information that the video does not cover. One is that the barrel of S stop needs to be screwed back into contact with the P stop. A second is that twisting the drill bit counterclockwise a little beyond the parallel marks will help when doing more than touch up grinding.
Loading of the grinding wheel proved to be factor I had to contend with. As it became loaded, the grinding noise quieted down causing me to think it had reached the stop before it actually had. For larger bits plan to use the stone grader more than once during the bit sharpening unless you only are doing touch up grinding.
Due to limited left hand usage, I have to operate the Tormek using my right hand only most of the time. Mr. Holtham tells you where to place your hands for best operating procedures. It took awhile to figure out the best operating position and the proper hand position for my situation. If I am not careful, the drill and holding fixture will climb up the grinding wheel due to the wheel rotating away from the cutting lip. I see where this could be an issue even for one using both hands. This tends to happen less when the wheel is kept clean of the loading issue. Would it be possible to reverse the motor direction so that the wheel would turn into the drill bit lip? Yes I know it probably won't happen at the factory because the honing wheel would be turning into the edges of tools when mounted in the jigs utilizing the USB in the horizontal position.
I think a person can reasonably expect the grinding to take longer than the video shows. I believe Ken said 12 minutes (not all that time was spent in sharpening as part was solely instructional) for the video. If you look at the close up of the drill bit at about the 10 minute 30 second point, you will notice that the left primary cutting lip, as you face it, appears to have a chip in it. I do not see it in the later close-up. Thus more grinding would have been required than was shown. Also I have to add quite a bit of time for my sharpening because I am not nearly proficient as he is.
Interesting post, Elden.
I agree, there is definitely a learning curve with the DBS-22. In my opinion, it is the most advanced of all the Tormek jigs. In the back of my head, I know that someday I must go through my drill index and regrind all the bits to four facet. I think that would either make me proficient or do me in!
You mention the possibility of reversing the direction of the motor. I am no expert, but I have seen some tool motors which can be reversed by switching two of the lead wires. I certainly understand why Tormek does not place a switch to reverse motor direction on all the units. In the general case this is quite logical. However, you are a skilled, experienced user with special requirements.
I believe keeping the grinding wheel in optimum cutting involves more of a learning/experience curve than most us, myself included, realize. Being aware of sound changes during grinding seems important. Yesterday I reran a five minute grinding test wuth the black stone. I could not understand why it did not outperform better than the standard stone grinding metal lathe tool bits (high speed steel with alloys). I redid the test after freshly truing the wheel. For most of the first minute, the stone made a powerful grinding sound. I was pleased. However, it quickly quieted down and gave me the same disappointing results the initial test produced. I do not know if my test is a good indicator. There may be factors I am unaware of. I do know that there was a definite change in the grinding sound. I have always paid attention to sound while grinding. I will intensify my focus in the future. I believe there is much to be learned by close observation. One of the many things I learned from being with Steve Bottorff for a day was how intensely observant he is of his grinding wheel. Intelligence, curiousity, persistency and experience make a powerful combination.
Do keep us posted.
Ken
ps Some guy recently posted a topic question in the Tormek general section about using one of the adaptor brackets to create a second horizontal position on the side where the wheel is incoming, as in the vertical position.
Ken,
My Foley 308 chainsaw chain grinder has a reversible motor controlled by which direction the switch is flipped. The current grinders are not made that way thanks to OSHA getting ants in their pants. I suppose it is dangerous for the sparks to be thrown toward the operator. It would be nice to have the Tormek able to be reversed in like manner.
I thought of mounting another horizontal base on the other side but the switch would have to be relocated. The USB could possibly tangle with the second horizontal mount when inserted into the first one as well. I'll try to check out the post you mentioned.
Small bits are proving to be a challenge to get the secondary bevels ground properly without destroying one of the primary bevels. I am trying to do a #8 bit (0.199") which is a little larger than the minimum 3/16" size (0.1875"). The primary angles were not too bad to do. Plan to try again today.
Elden,
I studied my Tormek (T7) earlier this evening to see if a fairly easy modification would be possible to add a second horizontal setting for the universal support.
A universal support with much longer "legs" would work nicely. Since I don't think that will happen, imagine this:
Look at your Tormek with the grinding wheel on the left. Push the long leg of the universal support through the horizontal sleeve next to the grinding wheel. That is the plane where the sleeves for the other side of the wheel would ned to be located.
I purchased an old XB 100 several years ago. I thought I had found a bargain. It was no bargain; it is the earlier model with only one holding screw. If you imagine one of the new, two screw XB-100 parts sitting between the vertical sleeves. The XB-100 should fit next to the sleeve on the grinding wheel side with no modification. A one inch diameter hole needs to be drilled in the XB-100 to slide over the right side sleeve. Once this is done, and the XB-100 fits flat against the Tormek housing, all that is needed is to drill the four holes for the mounting screws (already drilled in the XB-100) through the Tormek housing.
With this modification, your Tormek can be used in the horizontal position with the grinding wheel either coming into the work or trailing. No modification of the motor or switch is necessary.
The only other change needed would be changing the right sleeve tightening knob to a longer machine screw to clear the (vertical) sleeve.
I am thinking of having my Tormek modified this way. In my case, I will have the work done by a local machine shop. It should be a fairly simple job not involving much set up time.
Ken
Quote from: Ken S on April 14, 2015, 03:26:25 AM
I purchased an old XB 100 several years ago. I thought I had found a bargain. It was no bargain; it is the earlier model with only one holding screw.
Should be easy to drill and tap for another holding screw. It's soft aluminum.
By the way, I think Elden has the much older Tormek with a rectangular housing. Not sure how that affects this plan.
Thanks Ken. That is well thought out. I will have to check it out tomorrow.
Herman you are correct, mine is the old rectangular frame. The switch is located on the side of the top where the second horizontal sleeve base would be positioned. I will either have to relocate the switch or see if a hole could be cut for it in the base which may not be practical.
Thanks to both of you.
Today I worked on sharpening some small drill bits. In doing so I found out a few things about the use of the DBS-22.
It is possible to cause error to be introduced into the grinding due to improper pressure being placed on the attachment. If too much pressure is placed on the front of the drill bit holding fixture, flexing of the attachment can occur. Most is probably actually occurring in the slide areas. There may be a slight flexing of the USB as well.
Some drill bits do not form a straight cutting lip when they are ground. Some have a concave cutting lip. This causes a problem when grinding the secondary facets. By the time the "point" of the four facet drill is achieved, the cutting lip (primary bevel) has been destroyed or is too thin to be durable. Larger bits that have this concave have a wider primary facet and are not affected as much. Bits that do not have this concave lip make excellent four faceted bits.
Smaller bits than 3/16 can be sharpened CAREFULLY. Small bits flex. I did a 5/32 bit successfully today. There IS a limit to how small can be done.
On some small bits it is better to forget trying to get the point on the bit in my opinion.
The attachment is a good one.
Quote from: kb0rvo on April 13, 2015, 07:56:52 PM
My Foley 308 chainsaw chain grinder has a reversible motor controlled by which direction the switch is flipped. The current grinders are not made that way thanks to OSHA getting ants in their pants. I suppose it is dangerous for the sparks to be thrown toward the operator. It would be nice to have the Tormek able to be reversed in like manner.
Elden, it is not a problem to reverse a single phase induction motor. The simplest way, for testing purposes, is to disconnect the capacitor and start the motor by hand in the desired direction. :)
But, in my thinking, T7 motors may not be reversed, because they have the unique Tormek drive system. Its design is asymmetrical, the more load you put on the stone, the more the motor shaft is pressed against the rubberized friction wheel. Thanks to this special reduction gear the torque of the stone is tremendous.
Jan
Good point Jan. I hadn't thought about the drive mechanism possibly being compromised.
Thanks
Several very good points in need of response:
Herman, Yes, the Tormek jigs are easily drilled and tapped. I did that for the HK-40 and HK-50 I made. However, with the XB-100, the sleeve without the locking knob is thin, too thin for enough threads to be effective. It was redesigned when converted to the double locking mechanism. The newer version is a real improvement.
Elden, I forgot you had the square design Tormek.
Jan, good point about the motor and the drive train. I forgot about the drive train.
I believe we have a very possible solution. My question is whether or not it is practical. I can have my Tormek T7 modified to work well with the second horizontal position. The parts cost approximately thirty dollars, more if shipping is factored in. machining costs could easily be fifty to a hundred US dollars. Would this improvement justify the cost?
I don't have an immediate answer for the question. I will put it on the back burner and ponder it.
Ken
Quote from: Ken S on April 14, 2015, 04:57:04 PM
However, with the XB-100, the sleeve without the locking knob is thin, too thin for enough threads to be effective.
Ah, yes. I recall this issue. Perhaps one could drill a hole and epoxy a nut to the surface. Welding would be better, if that's even a possibility.
Or maybe counter sink a cap nut into the underside.
You are correct, Herman. However, for twenty seven US dollars I can go to my local Tormek dealer and purchase the current version of the XB-100. It is enough of an improvement that I believe my shop time would be better invested installing the improved version.
(I could also buy the older version on a prominent online auction site for thirty seven dollars. Caveat emptor.)
Ken
I'm going to really bug you all now:
I had no idea my linisher style tool could do drill bits until I was reading something the other day. Now for drill bits my grinding operation goes like this:
1/ set platform at 60 degrees to belt
2/ hold one side of drill bit to grinding medium and grind until you roughly eyeball the middle
3/ flip over and do the other side so the middle remains a point and remains central.
Job done. Total time taken, 20-30 seconds :-)
Whats more they drill like a knife through butter.
To me it seems the process you describe, Rob, would produce two flat surfaces that meet near the center. But don't you have to rotate the bit as you grind so that you produce two conical surfaces? Moreover those surfaces aren't really conical as the cone angle has to decrease as you move away from the cutting edge. I've seen the practiced hand do this with ease and speed. My dad would do this on his dry grinder. When I inherited his bits I had to properly sharpen them all with my Drill Doctor. I think that as he got older his hand-eye coordination started to fail a bit.
Kind of like sharpening a knife by hand. If you're good at it you make it look easy.
I was taught NEVER to rotate the drill bit when hand sharpening. The only time the drill bit should be rotated is when it is drilling a hole. A straight movement down (when using vertical grinders) away from the cutting lip to give the relief angle can be used. It does not have to be, however, as long as the necessary relief is formed. The DBS-22 forms straight bevels if you don't consider the hollow grind due to the round wheel.
The cutting lip should always held at 90° to the sides of the grinding wheel. That is why the cutting lips are placed parallel to the horizontal index mark on the DBS-22 holding fixture.
When using the Drill Doctor and the industrial models made by Darex, the bits are twisted when sharpening. However, they are engineered with a special cam action that forms the proper levels.
Quote from: Herman Trivilino on April 15, 2015, 07:17:08 PM
But don't you have to rotate the bit as you grind so that you produce two conical surfaces?
You do rotate them to exactly (by eye) half the circumference of the shaft to leave as you describe a cone before flipping over and repeating for the other half of the circumference.
To sharpen my drills I use a jig I designed, I was finding it difficult to get the angles accurate by hand. I have just tried the base of the scissor drill set at 59 deg. To use you place the cutting edge at 90 deg and grind then push outwards and downward to cut the clearance. This worked on the Tormec but it was very slow cutting even though the wheel was course dressed on the 6mm dormer drill I tried. Will send a picture of my jig shortly .
Garth
Picture of Drill Jig
(http://www.cotswoldsport.co.uk/misc_gc/Drill_jig1.jpg)
Quote from: harvestbarn on April 16, 2015, 12:50:40 PM
To sharpen my drills I use a jig I designed, I was finding it difficult to get the angles accurate by hand. I have just tried the base of the scissor drill set at 59 deg. To use you place the cutting edge at 90 deg and grind then push outwards and downward to cut the clearance. This worked on the Tormec but it was very slow cutting even though the wheel was course dressed on the 6mm dormer drill I tried. Will send a picture of my jig shortly .
Garth
Garth, thank you for sharing your experience. :)
It is highly inspiring for me because I do not have the drill bit attachment!
In my thinking the described procedure will lower the chisel cutting edge angle of the drill, but sharpening the lip clearance properly may be more important.
Jan
One is aiming for an angle of between 10 to 15 deg from the cutting edge to the end of the lip clearance while maintaining both cutting edges the same length.
This will only provide a chisel edge not the 4 facet point that the DBS-22 is capable, it has been very interesting hearing the comments from users thanks to all who have contributed. I do not yet have a Blackstone Silicon grindstone which I suspect is needed for sharpening drill bits on the Tormek.
Garth
Thank you for reminding the size of the lip relief angels. :)
In my thinking for small drill bit diameters and soft material we use high relief angels, while for large drill bit diameters and hard material we use low relief angels.
If I grasp your Tormek grinding procedure correctly, you rotate the drill bit with fingers, while pushing it outwards and downwards simultaneously. Is my understanding of this correct?
Jan
Garth,
I would not delay drill bit sharpening because you do not yet have a black stone. I did a preliminary test comparing the SG regular grinding stone and the SB black stone. My test was not comprehensive, however, I did not notice any difference between the results of the regular and black stones. Further testing and the need to sharpen many drill bits on a regular basis might lean me more toward the black stone, however, at this point, I am quite satisfied with the regular stone for sharpening standard high speed drill bits. If sharpening high speed steel causes the SG stone to wear a little more quickly, I have no problem with that. I consider grinding wheels consumables, like brake shoes.
The Tormek DBS-22 is quite a nice jig. I consider it the most advanced and versatile of all the Tormek jigs. (It is priced accordingly.) The design and machining is very well done. It can handle many drill bit angle configurations. The four facet grinding is well beyond the standard grind. A serious drill bit sharpener will be well satisfied with this jig.
That said, I think the person who occasionally wants to sharpen a drill bit could self design a modification of the platform or scissors jig (much like the HK 50 or HK40) to do a basic sharpening of drill bits. Drilling a smaller pilot hole would help keep the bit with standard grind aligned. This is a standard machine shop practice.
Ken
Quote from: Herman Trivilino on April 15, 2015, 07:17:08 PM
To me it seems the process you describe, Rob, would produce two flat surfaces that meet near the center. But don't you have to rotate the bit as you grind so that you produce two conical surfaces? Moreover those surfaces aren't really conical as the cone angle has to decrease as you move away from the cutting edge. I've seen the practiced hand do this with ease and speed. My dad would do this on his dry grinder. When I inherited his bits I had to properly sharpen them all with my Drill Doctor. I think that as he got older his hand-eye coordination started to fail a bit.
Kind of like sharpening a knife by hand. If you're good at it you make it look easy.
It is a pleasant duty to properly sharpen all inherited tools, including old drill bits. :)
When re-sharpening an old drill bit repeatedly, we inevitably form a longer
chisel edge length, because the web thickness is usually increasing towards the shank of the drill bit.
Drill bit web does not contribute to the cutting process, on the contrary it consumes power and torque, and generates heat. The only positive thing on forming longer chisel edge is, that we move this drill bit to heavy duty category.
Jan
P.S.
Drill bit nomenclature and geometry is nicely described at http://neme-s.org/2005%20May%20Meeting/drills.pdf (http://neme-s.org/2005%20May%20Meeting/drills.pdf)
(http://img1.rajce.idnes.cz/d0101/11/11283/11283097_fa252b273beea2a39e3ea2129b2ee25e/images/Drill_CHISEL_EDGE.jpg?ver=0)
Jan, that is excellent information. I missed seeing your post until today.
I have wondered about the difference between a split point and a four facet grind. It appears to be only that the four facet does not have to come entirely to a split point, albeit, it may. Split points have been around for years. Darex bit grinders, the maker of the Drill Doctor and more industrial models, have had this capability for years.
Looking at the information Jan posted, it seems to me that as the web thickness increases the advantage of a split point increases. Would this also be true of the four-facet grind?
Thank you Elden and Herman for your responses. :) I am surely not a drill bit specialist.
Recently I saw Robert Gilman's video introducing Drill Doctor. I was surprised by his statement that the drill bit chisel edge is involved in cutting process. I my thinking the chisel edge does not cut, but penetrates the material. Chisel edge consumes part of power and torque, generates heat and for those reasons its length should be reasonably small. If the split point technique will reduce the total chisel edge length, than such a drill bit may be mechanically more efficient than the standard grinded drill bit.
Jan
Jan, splitting the point, as I understand it, theoretically reduces the chisel edge length to zero. The intent is to reduce or prevent "wandering" of the bit when you begin to drill into something hard like steel.
(http://i1291.photobucket.com/albums/b553/htrivilino/Modified%20split%20point%20MSP_zpszlsuvfno.jpg) (http://s1291.photobucket.com/user/htrivilino/media/Modified%20split%20point%20MSP_zpszlsuvfno.jpg.html)
Thanks for the explanation, Herman. :)
I do not have neither the DBS-22 nor the Drill Doctor, so I am contemplating how to sharpen drill bits using T7 and a slightly modified Tool Rest. Because I am conservative, I plan standard drill bit grinding, as it was invented by Steven A. Morse in 1861.
I would like to master the knack of your dad!
Jan
Jan,
Ernie Conover did an excellent you tube for Fine Woodworking about using standard metal drill bits for precision drilling of wood. Ernie just uses the standard biy grind. However, following good machine shop practice, he first drills a considerably smaller pilot hole. Next he enlarges the pilot hole with a drill bit just slightly smaller than his final diameter. The third hole is drilled with the actual diameter bit. It removes very little wood, and can drill a very accurate hole.
Ken
Herman, the picture you posted is a modified split point instead of a standard split point. This article, which has been previously posted, shows a split point (which they and Tormek call "four facet") as well as other kinds of points.
http://www.mmsonline.com/articles/choose-the-best-drill-point-geometry
It appears to me, a split point still has a portion of the chisel edge remaining from the primary bevel grinding, although it has been tapered off by the secondary bevel grinding. A drill bit with a thick web makes this very noticeable. I think the modified split point would help relieve it a little more and might require even a little less pressure than a normal split point. However, this is only supposition on my part.
Quote from: Ken S on May 01, 2015, 02:32:26 AM
Jan,
Ernie Conover did an excellent you tube for Fine Woodworking about using standard metal drill bits for precision drilling of wood. Ernie just uses the standard biy grind. However, following good machine shop practice, he first drills a considerably smaller pilot hole. Next he enlarges the pilot hole with a drill bit just slightly smaller than his final diameter. The third hole is drilled with the actual diameter bit. It removes very little wood, and can drill a very accurate hole.
Ken
Thank you Ken for your comment and reference to Ernie Conover. :)
I usually use a two-step process, the pilot hole followed by the final diameter. The three-step procedure is surely better, but you spent more time swapping drill bits.
Jan
Drill bit geometry is very interesting and important topic. The MMS leaflet referenced by Elden is excellent reading. :)
Let me set the drill bit geometry theory aside for a while. I would like to mention a real word example.
Recently I made decorative roof, above the door to the garden, of ¼" thick steel sheet, which required drilling several dozens of holes. All I needed for drilling the holes, were two conventional twist drill bits. One 1/8 " for the pilot hole and the other 1/4 " for the final diameter. Both drill bits are still usable.
(http://img19.rajce.idnes.cz/d1903/11/11283/11283097_fa252b273beea2a39e3ea2129b2ee25e/images/Roof.jpg?ver=0)
The steel part of the roof was cut using the abrasive waterjet cutting technology.
Jan
That was a lot of drilling, Jan. I trust you were using a drill press.
Yes, Elden it was a lot of drilling. Fortunately I have a radial arm drill press. :)
I have used drill bits designed for drilling holes for rivets. Those drill bits are very short and have flutes on both ends.
(http://www.toolcobber.com.au/wp-content/uploads/2012/02/Rivet-Drill-Bit.jpg)
I always use suitable cutting fluid to cool and lubricate the drill bit.
Jan
Quote from: Elden on April 14, 2015, 05:23:40 AM
It is possible to cause error to be introduced into the grinding due to improper pressure being placed on the attachment. If too much pressure is placed on the front of the drill bit holding fixture, flexing of the attachment can occur. Most is probably actually occurring in the slide areas. There may be a slight flexing of the USB as well.
Hi Everyone, I have just purchased a DBS-22 and have also noticed quite a lot of play between the attachment and the mounting plate. What seems to happen the rubber strips can be compressed on one side or another causing a change in angle of the drill bit. This becomes more noticeable the smaller the drill bit. As I'm sharpening I have to be very careful to keep the attachment stable as I go back and forth across the wheel.
Could Tormek replace the rubber with some ball bearings perhaps? (metal filings might be the reason they havent already?
Cheers John